From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FF3BC67871 for ; Thu, 27 Oct 2022 10:32:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 01F728E0003; Thu, 27 Oct 2022 06:32:34 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F12988E0001; Thu, 27 Oct 2022 06:32:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E02038E0003; Thu, 27 Oct 2022 06:32:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id D1E888E0001 for ; Thu, 27 Oct 2022 06:32:33 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 982F51208CE for ; Thu, 27 Oct 2022 10:32:33 +0000 (UTC) X-FDA: 80066365386.19.E3C1557 Received: from mail-lf1-f46.google.com (mail-lf1-f46.google.com [209.85.167.46]) by imf30.hostedemail.com (Postfix) with ESMTP id 16B0780039 for ; Thu, 27 Oct 2022 10:32:32 +0000 (UTC) Received: by mail-lf1-f46.google.com with SMTP id j16so1831598lfe.12 for ; Thu, 27 Oct 2022 03:32:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=w9inep0ICkxp/dh4usTOKJg2DS4O/PjgYL7PaxVj8nE=; b=He3KNTA1uzdE+/30x0YAVnNT5LBT5F0pcE0sreR/6bcka+epVOp76U2hyy/CJSoIWG JAihFvvF9sM2iIjsygXbKnpSRxID6/+2sxio+dS4ewdgbad1wi2NXa5tJu3x5tqeYAlv UtwVYg/Gcz+8DVhBpHR18MqsvICc+m4RrJNsqjJdudUlbeYy6aTkaIaf3eIv+ud8E0dS v0xM+7J9B5tIEL/Qk7yS0snDMleZCnQFQY8rFnBErl150YutcwpBck5S45m5SyeCV7IY /qppO0QgFlw/GYMI8ahdr8CaUo6HI4z+itdyiAxSpobBblxfNNpqOMXqWbb/ABnAhazV 1utw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=w9inep0ICkxp/dh4usTOKJg2DS4O/PjgYL7PaxVj8nE=; b=tw/M4KZKPLkdlcHbRP6kfPxdutua3jtPVlUecT+KaODZ8PppZ6dQZeaFoPOMikwSGl yFrzxP8ybJtJuFBFxSf05L62Jj5DhM6U26pq2jSMd0MDDvBg9lkdgYDcRaP0VBLN6t4g GILNkf9irfQHUHNalA1tQ9Aj0TXcgicmoEQFzo8z/+4woKYa70LwG8Ag+o/Q10kwZjC8 8lSSXXZizx/2/QnQYX4TncodZyhsQdVIxw1qwxJ5a7lN+V4G4yeF0hxqbU+YuIKFnY5Q 6WJ3qD5WQEaIHYaSkL2JgUBwsnRJi5sf7ALstbwRBWDE47NkFiU5XKfFJmgpZhWBe4Ov vq7g== X-Gm-Message-State: ACrzQf3ukmFBg3/EOQ6w+/zhPwrjJuNYQfZA+WpptppG0S83/cnSzHw2 oA5dR+3JJgV48BnZBRMUGwdJHyOgQ+f7n5xTRBXiTw== X-Google-Smtp-Source: AMsMyM5dAHAxPv2Bh6GmPPoRfi0elzyRurwu9CzNvbiRQf0ph34a5+/yC7zAjnQ5zj+Z1llGVrUaWyE+xmS18u2wiYI= X-Received: by 2002:a05:6512:3119:b0:4a2:d749:ff82 with SMTP id n25-20020a056512311900b004a2d749ff82mr18771133lfb.637.1666866751285; Thu, 27 Oct 2022 03:32:31 -0700 (PDT) MIME-Version: 1.0 References: <20221025151344.3784230-1-chao.p.peng@linux.intel.com> <20221025151344.3784230-9-chao.p.peng@linux.intel.com> In-Reply-To: <20221025151344.3784230-9-chao.p.peng@linux.intel.com> From: Fuad Tabba Date: Thu, 27 Oct 2022 11:31:54 +0100 Message-ID: Subject: Re: [PATCH v9 8/8] KVM: Enable and expose KVM_MEM_PRIVATE To: Chao Peng Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org, Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , Michael Roth , mhocko@suse.com, Muchun Song , wei.w.wang@intel.com Content-Type: text/plain; charset="UTF-8" ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666866753; a=rsa-sha256; cv=none; b=0zACpUvtacfAJEfg8saWVQVtr4VbPF/QehLphbSBSBWcqLHWTx9U7/EsXQ8uJ3mM8Cxq84 H5fBloUgiv+eLBHZLXEi4bp+BDOjLICUi4CvD5HMHwc6pyXT8OS078jPtOIRrdrBSVsc19 0FJCU0fjVyLh+ZG1kstg5azpmunCVa8= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=He3KNTA1; spf=pass (imf30.hostedemail.com: domain of tabba@google.com designates 209.85.167.46 as permitted sender) smtp.mailfrom=tabba@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666866753; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=w9inep0ICkxp/dh4usTOKJg2DS4O/PjgYL7PaxVj8nE=; b=mZVL+ZBX9UmbyxR4UVasWsZoZ0mGSZJJZVmgiYVBJsIOXcySQX+q1veeKi2r96umP6l3i1 vc9EUdaFFqPivBKF4vgRdgnnuNtzyb/hpuI+j1NbCnw5V3AxxfGyyfyCGPUV7lpHmxWxqz NJemIOOdYMqVAwhSldGXeWKZUwh1AIg= X-Stat-Signature: x71sd5w3ph189h6khs6kt771p3n3c9gn X-Rspamd-Queue-Id: 16B0780039 Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=He3KNTA1; spf=pass (imf30.hostedemail.com: domain of tabba@google.com designates 209.85.167.46 as permitted sender) smtp.mailfrom=tabba@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1666866752-854721 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi, On Tue, Oct 25, 2022 at 4:20 PM Chao Peng wrote: > > Expose KVM_MEM_PRIVATE and memslot fields restricted_fd/offset to > userspace. KVM register/unregister private memslot to fd-based > memory backing store and responses to invalidation event from > restrictedmem_notifier to zap the existing memory mappings in the > secondary page table. > > Whether KVM_MEM_PRIVATE is actually exposed to userspace is determined > by architecture code which can turn on it by overriding the default > kvm_arch_has_private_mem(). > > A 'kvm' reference is added in memslot structure since in > restrictedmem_notifier callback we can only obtain a memslot reference > but 'kvm' is needed to do the zapping. > > Co-developed-by: Yu Zhang > Signed-off-by: Yu Zhang > Signed-off-by: Chao Peng > --- > include/linux/kvm_host.h | 3 +- > virt/kvm/kvm_main.c | 174 +++++++++++++++++++++++++++++++++++++-- > 2 files changed, 171 insertions(+), 6 deletions(-) Reviewed-by: Fuad Tabba Thanks, /fuad > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 69300fc6d572..e27d62c30484 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -246,7 +246,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); > #endif > > > -#if defined(KVM_ARCH_WANT_MMU_NOTIFIER) || defined(CONFIG_KVM_GENERIC_PRIVATE_MEM) > +#if defined(KVM_ARCH_WANT_MMU_NOTIFIER) || defined(CONFIG_HAVE_KVM_RESTRICTED_MEM) > struct kvm_gfn_range { > struct kvm_memory_slot *slot; > gfn_t start; > @@ -583,6 +583,7 @@ struct kvm_memory_slot { > struct file *restricted_file; > loff_t restricted_offset; > struct restrictedmem_notifier notifier; > + struct kvm *kvm; > }; > > static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *slot) > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 13a37b4d9e97..dae6a2c196ad 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1028,6 +1028,111 @@ static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, > } > #endif /* CONFIG_KVM_GENERIC_PRIVATE_MEM */ > > +#ifdef CONFIG_HAVE_KVM_RESTRICTED_MEM > +static bool restrictedmem_range_is_valid(struct kvm_memory_slot *slot, > + pgoff_t start, pgoff_t end, > + gfn_t *gfn_start, gfn_t *gfn_end) > +{ > + unsigned long base_pgoff = slot->restricted_offset >> PAGE_SHIFT; > + > + if (start > base_pgoff) > + *gfn_start = slot->base_gfn + start - base_pgoff; > + else > + *gfn_start = slot->base_gfn; > + > + if (end < base_pgoff + slot->npages) > + *gfn_end = slot->base_gfn + end - base_pgoff; > + else > + *gfn_end = slot->base_gfn + slot->npages; > + > + if (*gfn_start >= *gfn_end) > + return false; > + > + return true; > +} > + > +static void kvm_restrictedmem_invalidate_begin(struct restrictedmem_notifier *notifier, > + pgoff_t start, pgoff_t end) > +{ > + struct kvm_memory_slot *slot = container_of(notifier, > + struct kvm_memory_slot, > + notifier); > + struct kvm *kvm = slot->kvm; > + gfn_t gfn_start, gfn_end; > + struct kvm_gfn_range gfn_range; > + int idx; > + > + if (!restrictedmem_range_is_valid(slot, start, end, > + &gfn_start, &gfn_end)) > + return; > + > + idx = srcu_read_lock(&kvm->srcu); > + KVM_MMU_LOCK(kvm); > + > + kvm_mmu_invalidate_begin(kvm, gfn_start, gfn_end); > + > + gfn_range.start = gfn_start; > + gfn_range.end = gfn_end; > + gfn_range.slot = slot; > + gfn_range.pte = __pte(0); > + gfn_range.may_block = true; > + > + if (kvm_unmap_gfn_range(kvm, &gfn_range)) > + kvm_flush_remote_tlbs(kvm); > + > + KVM_MMU_UNLOCK(kvm); > + srcu_read_unlock(&kvm->srcu, idx); > +} > + > +static void kvm_restrictedmem_invalidate_end(struct restrictedmem_notifier *notifier, > + pgoff_t start, pgoff_t end) > +{ > + struct kvm_memory_slot *slot = container_of(notifier, > + struct kvm_memory_slot, > + notifier); > + struct kvm *kvm = slot->kvm; > + gfn_t gfn_start, gfn_end; > + > + if (!restrictedmem_range_is_valid(slot, start, end, > + &gfn_start, &gfn_end)) > + return; > + > + KVM_MMU_LOCK(kvm); > + kvm_mmu_invalidate_end(kvm, gfn_start, gfn_end); > + KVM_MMU_UNLOCK(kvm); > +} > + > +static struct restrictedmem_notifier_ops kvm_restrictedmem_notifier_ops = { > + .invalidate_start = kvm_restrictedmem_invalidate_begin, > + .invalidate_end = kvm_restrictedmem_invalidate_end, > +}; > + > +static inline void kvm_restrictedmem_register(struct kvm_memory_slot *slot) > +{ > + slot->notifier.ops = &kvm_restrictedmem_notifier_ops; > + restrictedmem_register_notifier(slot->restricted_file, &slot->notifier); > +} > + > +static inline void kvm_restrictedmem_unregister(struct kvm_memory_slot *slot) > +{ > + restrictedmem_unregister_notifier(slot->restricted_file, > + &slot->notifier); > +} > + > +#else /* !CONFIG_HAVE_KVM_RESTRICTED_MEM */ > + > +static inline void kvm_restrictedmem_register(struct kvm_memory_slot *slot) > +{ > + WARN_ON_ONCE(1); > +} > + > +static inline void kvm_restrictedmem_unregister(struct kvm_memory_slot *slot) > +{ > + WARN_ON_ONCE(1); > +} > + > +#endif /* CONFIG_HAVE_KVM_RESTRICTED_MEM */ > + > #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER > static int kvm_pm_notifier_call(struct notifier_block *bl, > unsigned long state, > @@ -1072,6 +1177,11 @@ static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot) > /* This does not remove the slot from struct kvm_memslots data structures */ > static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) > { > + if (slot->flags & KVM_MEM_PRIVATE) { > + kvm_restrictedmem_unregister(slot); > + fput(slot->restricted_file); > + } > + > kvm_destroy_dirty_bitmap(slot); > > kvm_arch_free_memslot(kvm, slot); > @@ -1643,10 +1753,16 @@ bool __weak kvm_arch_has_private_mem(struct kvm *kvm) > return false; > } > > -static int check_memory_region_flags(const struct kvm_user_mem_region *mem) > +static int check_memory_region_flags(struct kvm *kvm, > + const struct kvm_user_mem_region *mem) > { > u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; > > +#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM > + if (kvm_arch_has_private_mem(kvm)) > + valid_flags |= KVM_MEM_PRIVATE; > +#endif > + > #ifdef __KVM_HAVE_READONLY_MEM > valid_flags |= KVM_MEM_READONLY; > #endif > @@ -1722,6 +1838,9 @@ static int kvm_prepare_memory_region(struct kvm *kvm, > { > int r; > > + if (change == KVM_MR_CREATE && new->flags & KVM_MEM_PRIVATE) > + kvm_restrictedmem_register(new); > + > /* > * If dirty logging is disabled, nullify the bitmap; the old bitmap > * will be freed on "commit". If logging is enabled in both old and > @@ -1750,6 +1869,9 @@ static int kvm_prepare_memory_region(struct kvm *kvm, > if (r && new && new->dirty_bitmap && (!old || !old->dirty_bitmap)) > kvm_destroy_dirty_bitmap(new); > > + if (r && change == KVM_MR_CREATE && new->flags & KVM_MEM_PRIVATE) > + kvm_restrictedmem_unregister(new); > + > return r; > } > > @@ -2047,7 +2169,7 @@ int __kvm_set_memory_region(struct kvm *kvm, > int as_id, id; > int r; > > - r = check_memory_region_flags(mem); > + r = check_memory_region_flags(kvm, mem); > if (r) > return r; > > @@ -2066,6 +2188,10 @@ int __kvm_set_memory_region(struct kvm *kvm, > !access_ok((void __user *)(unsigned long)mem->userspace_addr, > mem->memory_size)) > return -EINVAL; > + if (mem->flags & KVM_MEM_PRIVATE && > + (mem->restricted_offset & (PAGE_SIZE - 1) || > + mem->restricted_offset > U64_MAX - mem->memory_size)) > + return -EINVAL; > if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM) > return -EINVAL; > if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) > @@ -2104,6 +2230,9 @@ int __kvm_set_memory_region(struct kvm *kvm, > if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages) > return -EINVAL; > } else { /* Modify an existing slot. */ > + /* Private memslots are immutable, they can only be deleted. */ > + if (mem->flags & KVM_MEM_PRIVATE) > + return -EINVAL; > if ((mem->userspace_addr != old->userspace_addr) || > (npages != old->npages) || > ((mem->flags ^ old->flags) & KVM_MEM_READONLY)) > @@ -2132,10 +2261,28 @@ int __kvm_set_memory_region(struct kvm *kvm, > new->npages = npages; > new->flags = mem->flags; > new->userspace_addr = mem->userspace_addr; > + if (mem->flags & KVM_MEM_PRIVATE) { > + new->restricted_file = fget(mem->restricted_fd); > + if (!new->restricted_file || > + !file_is_restrictedmem(new->restricted_file)) { > + r = -EINVAL; > + goto out; > + } > + new->restricted_offset = mem->restricted_offset; > + } > + > + new->kvm = kvm; > > r = kvm_set_memslot(kvm, old, new, change); > if (r) > - kfree(new); > + goto out; > + > + return 0; > + > +out: > + if (new->restricted_file) > + fput(new->restricted_file); > + kfree(new); > return r; > } > EXPORT_SYMBOL_GPL(__kvm_set_memory_region); > @@ -4604,6 +4751,11 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) > case KVM_CAP_BINARY_STATS_FD: > case KVM_CAP_SYSTEM_EVENT_DATA: > return 1; > +#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM > + case KVM_CAP_PRIVATE_MEM: > + return 1; > +#endif > + > default: > break; > } > @@ -4795,16 +4947,28 @@ static long kvm_vm_ioctl(struct file *filp, > } > case KVM_SET_USER_MEMORY_REGION: { > struct kvm_user_mem_region mem; > - unsigned long size = sizeof(struct kvm_userspace_memory_region); > + unsigned int flags_offset = offsetof(typeof(mem), flags); > + unsigned long size; > + u32 flags; > > kvm_sanity_check_user_mem_region_alias(); > > + memset(&mem, 0, sizeof(mem)); > + > r = -EFAULT; > + if (get_user(flags, (u32 __user *)(argp + flags_offset))) > + goto out; > + > + if (flags & KVM_MEM_PRIVATE) > + size = sizeof(struct kvm_userspace_memory_region_ext); > + else > + size = sizeof(struct kvm_userspace_memory_region); > + > if (copy_from_user(&mem, argp, size)) > goto out; > > r = -EINVAL; > - if (mem.flags & KVM_MEM_PRIVATE) > + if ((flags ^ mem.flags) & KVM_MEM_PRIVATE) > goto out; > > r = kvm_vm_ioctl_set_memory_region(kvm, &mem); > -- > 2.25.1 >